Viral Hepatitis

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Hepatitis Viruses - The Nasty Lineup

⭐ Hepatitis B is a DNA virus; all others (A, C, D, E) are RNA viruses.

  • Classification: Grouped by genome & transmission.
    • RNA Viruses: HAV, HCV, HDV, HEV
    • DNA Virus: HBV
  • Transmission & Chronicity:
    • 📌 Vowels (A, E): Faecal-oral, Acute, No chronicity (Except HEV in immunocompromised).
    • Consonants (B, C, D): Parenteral/Sexual, Chronic potential.

Hepatitis virus comparison and genome diagrams

  • Hepatitis D (Delta): Defective virus, requires HBsAg for replication; superinfection (worse) or coinfection with HBV.

Hepatitis A & E - The Fleeting Foes

  • RNA viruses, faecal-oral transmission. Acute, self-limiting hepatitis; no chronic state (except rare HEV G3). 📌 Mnemonic: "Vowels to the bowels" (A & E).
FeatureHepatitis A (HAV)Hepatitis E (HEV)
TransmissionFaecal-oral (food/water)Faecal-oral (water); Zoonotic (pigs)
Incubation (wks)2-62-10
SeverityMilder, esp. childrenSevere in adults; fulminant risk
DiagnosisAnti-HAV IgMAnti-HEV IgM; HEV RNA
ComplicationsRare: cholestatic, relapsingFulminant; chronic (G3, immunosuppressed)
PreventionVaccine; hygieneHygiene; safe water; (Vaccine not routine in India)
🤰 PregnancyBenign↑↑ Mortality (20-30% 3rd trim. G1/G2)

Hepatitis B - The Persistent Peril

⭐ The presence of HBsAg for more than 6 months defines chronic Hepatitis B infection.

  • Transmission: Parenteral (needles, blood), perinatal (mother-to-child), sexual.
  • Risk of Chronicity: Perinatal >90%; Early childhood 25-30%; Adult <5%.
  • Key Serological Markers: 📌 Mnemonic: 'S'-Surface/Screening, 'c'-Core/Chronic, 'e'-Envelope/Extra-contagious.
MarkerInterpretation
HBsAgActive infection (Acute/Chronic)
Anti-HBsImmunity (Vaccine/Resolved)
Anti-HBc IgMAcute infection (<6 months)
Anti-HBc TotalPast/current exposure
HBeAgHigh replication, ↑ infectivity
Anti-HBeLow replication, ↓ infectivity (seroconv.)
  • Phases of Chronic HBV (HBsAg+ >6 months):
  • Treatment Consideration (Chronic HBV): HBV DNA >20,000 IU/mL (HBeAg+) or >2,000 IU/mL (HBeAg-) with ↑ALT or significant fibrosis/cirrhosis.

Hepatitis C - The Stealthy Scourge

  • RNA virus, high chronicity rate (>70%). Parenteral transmission (needles, blood).
  • Genotypes: 6 major (GT 1-6). India: GT3 most prevalent, followed by GT1.
  • Extrahepatic Manifestations (EHM): 📌 'C's: Cryoglobulinemia (mixed), Cutanea tarda (Porphyria), Cancer (HCC), CNS involvement, Cardiomyopathy, Membranoproliferative Glomerulonephritis (MPGN). HCV extrahepatic manifestations diagram
  • Diagnosis: Anti-HCV antibodies (screen); HCV RNA PCR (confirms active infection, monitors treatment response).
  • Treatment: Direct-Acting Antivirals (DAAs).
    • Goal: SVR12 (Sustained Virologic Response 12 weeks post-treatment) = cure.
    • Pan-genotypic regimens (e.g., Sofosbuvir/Velpatasvir) are preferred.
  • ⭐ > Mixed cryoglobulinemia is a well-known extrahepatic manifestation of chronic Hepatitis C infection.

Hepatitis D - The Dependent Deviant

  • Defective RNA virus; requires HBsAg for replication & transmission.
FeatureCoinfection (HBV + HDV simultaneously)Superinfection (HDV in chronic HBV)
TimingAcute, self-limited (usually)Acute exacerbation, often chronic
SeveritySevere acute hepatitis; ↑ fulminant risk↑↑ Fulminant hepatitis, cirrhosis risk
IgM anti-HDVTransiently positivePersistently positive
IgG anti-HDVAppears late, may persistAppears early, high titres
  • Diagnosis: Anti-HDV antibodies (IgM, IgG), HDV RNA.
  • No specific treatment for HDV; HBV vaccination prevents HDV coinfection. PegIFN-alpha (low success).

High‑Yield Points - ⚡ Biggest Takeaways

  • HAV: Fecal-oral transmission, acute infection only; IgM anti-HAV diagnoses.
  • HBV: Parenteral/sexual transmission; chronic risk (cirrhosis, HCC); HBsAg (infection), Anti-HBs (immunity), HBeAg (infectivity).
  • HCV: Primarily parenteral (IVDU); high chronic infection risk (cirrhosis, HCC); HCV RNA confirms active infection.
  • HDV: Defective virus requiring HBV co-infection or superinfection (worse prognosis).
  • HEV: Fecal-oral (waterborne); high mortality in pregnant women (genotypes 1,2); chronic in immunosuppressed.
  • HBV window period: Anti-HBc IgM is the sole serological marker.
  • Vaccines: Available for HAV & HBV; no vaccine for HCV.

Practice Questions: Viral Hepatitis

Test your understanding with these related questions

With which of the following types of viral hepatitis infection in pregnancy is maternal mortality the highest?

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Flashcards: Viral Hepatitis

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The best prognostic indicator in chronic hepatitis C infection is the _____.

TAP TO REVEAL ANSWER

The best prognostic indicator in chronic hepatitis C infection is the _____.

liver biopsy

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